As a backlight arranged on a back surface of a liquid crystal panel used for a liquid crystal display apparatus, an edge-lighting type backlight is widely used in terms of compactness of the liquid crystal display apparatus.
In the edge-lighting type backlight, at least one end surface of a light guide sheet having a rectangular shape is used as a light incident end surface. Adjacent to the light incident end surface, a line-shaped primary light source such as a straight tube fluorescent lamp or a dot-shaped primary light source such as a light emitting diode (LED) is arranged along the light incident end surface. The light emitted from the primary light source enters from the light incident end surface of the light guide sheet, and after that, the light is introduced into the light guide sheet. The light is emitted from the light emitting surface of the one of two principal surfaces of the light guide sheet. The light emitted from the light emitting surface of the light guide sheet is diffused with a light diffusing element such as a light diffusing film and a light deflecting element such as a prism sheet, which are arranged on the light emitting surface to be deflected in the required direction.
On the back surface of the other principal surface of the two principal surfaces of the light guide sheet, a light reflecting element such as a light reflecting sheet is arranged to face the back surface in order to return the light emitted from the back surface to the light guide sheet.
On the light emitting surface of the light guide article or the back surface thereof, a light emitting organization having a function for emitting light is formed. For the light emitting organization, for example, it may be used a micro-concave-convex structure such as a rough surface which is moderately roughened or a lens-line forming surface where many lens-lines are arranged.
As a method of forming such a micro-concave-convex structure, for example, it may be exemplified a method of molding a resin shaped-article with use of a molding apparatus using a mold member for molding where concave-convex shapes are formed on the surface with blasting, cutting or the like, and transferring the concave-convex shapes to the surface of the resin shaped-article and a method of forming a foamed layer on a surface of the resin shaped-article.
For example, Patent Document 1 discloses a method of forming a foamed surface layer on a principal surface of a sheet-shaped light guide article-preform which is obtained with a methacrylic resin having a high molecular mass produced with cast polymerization with use of a laser irradiation processing.
In addition, Patent Document 2 discloses a method of irradiation by laser after impregnating a thermoplastic resin shaped-article with carbon dioxide and/or nitrogen.